"Okay...so we have tried everything to get 15-month-old Edie back to sleep in the middle of the night and to get her to sleep later in the morning. Here's the run-down: she sleeps only until 4:30-5 AM and wakes up in the night, often to stay awake for extended stretches. We have tried everything: rocking, co-sleeping (she won't sleep in our bed-- just thinks it's a chance for play), medicine when it seems needed (Orajel, Motrin, etc.), massage, sleeping by her crib, sitting by her crib patting her back, earlier bedtime, later bedtime, changed naptimes, different foods, etc. Absolutely nothing works. When she wakes up in the middle of the night, she will just sit there, eyes wide open, and then the second I leave or my husband leaves her room, she's screaming. And this can go on for hours; sometimes she's awake for 3-4 hours at a time in the middle of the night.
So at what point do you just go with cry it out? Last night we did that. She cried off and on (more off than on, but with regular crying jags) from 2 AM to 5:30 AM. She's one of those high-needs babies who still has to be rocked to sleep. Will this change if she's able to get herself to sleep without rocking? Will it change if I stop giving her a bottle before bed? Will it just change when she grows out of whatever phase she's in or gets whatever teeth she's getting...? I know there isn't a hard-and-fast answer to any of these questions, but I'm interested in ANY AND ALL input."
This is just so frustrating. 15 months is usually when kids really start to sleep all the way through if they haven't been before, even if it's not every single night.
The first thing that hit me is that this may be some strange kind of night terror. What makes me think that is that she wakes up and stares and then is inconsolable. (Here's my post that discusses night terrors. Scroll down to the comments--I didn't have the answer--to see the only solution that seems to consistently work, which is waking the child up 15-20 minutes before the night terrors usually happen--and then letting her go back to sleep--so the cycle is interrupted.)
So the first thing I'd do is see if the solution to night terrors helps you daughter. If it does, then it was pretty simple. The second thing I'd do is offer a snack. She's probably really mobile at this age, and she might just be really hungry in the middle of the night.
If neither of those help, then you're going to have to do a little more work (although not necessarily more than you're doing now). It sounds like even going in to comfort her doesn't actually comfort her or get her back to sleep, so it's not a choice of comfort her to sleep vs. cry it out. It's more like "what is possibly going to get my kid to sleep???".
As much as the CIO people* want us to think that every baby will cry to sleep, there's plenty of testimony to the contrary. Some kids just get more and more upset the longer they cry. So before you do CIO, you really have to figure out how it's going to affect your kid. If your kid releases tension by crying, then it's probably going to work to help the kid settle down**. If, however, you have have a kid who gains tension or anxiety by crying, then doing CIO is just shooting yourself in the foot, because crying is going to make it worse.
The upshot of all that is that you have to observe your own baby (and every subsequent baby, because kids can be radically different from their siblings) to see how crying affects them. That's the only way to know if you're being "forced" to do CIO. (I really don't think anyone's ever "forced" to do it. If your kid releases tension by crying, then you're helping them fall asleep by letting them release that tension, and you aren't being "forced." If your kid gets worse by crying, then you shouldn't let yourself be forced or talked into CIO because it's going to make everything worse. But my basic philosophy about parenting is you have to make your decision and then make peace with it, so I think feeling "forced" into doing something is counterproductive anyway, unless it's something you really were forced by someone else into doing.)
But back to Amy's specific problem. If I were in that situation, I'd spend a lot of time during the daytime talking about how nighttime is for sleeping, and Edie is a big girl and can go back to sleep when she wakes up. I might even buy a new musical lovey that Edie can turn on herself. I'd leave a bottle of water where she can reach it (which they don't make cupholders for cribs I'll never know). I would definitely not change anything about her bedtime routine if it gets her to bed and asleep willingly, since the problem is waking up later. I would talk about what the night-waking routine is going to be. Amy, you and your partner are going to make this up, but have it always be the same thing no matter which one of you is doing it. I'd probably go with some variation of coming in and quietly shhing her, offering the bottle of water (to reinforce that it's in there with her) and helping her turn on the musical lovey. Then say goodnight and leave. She's going to cry, but it sounds like she cries whether you're in there comforting her or not.
I don't think this is going to work overnight. And I don't think the crying is the key part. I think the talking about it, and giving her other tools to help her sleep (the lovey and the water and the consistent routine of what happens when she wakes up), and talking about it, and talking about it is what's going to help her. Or maybe she'll just grow into sleeping, but you and I will think my advice helped you when in reality it did nothing the passage of time wasn't going to do.
I hope you can fix the situation by waking her up right before she usually wakes up, and don't have to go through any of the rigamarole of a middle-of-the-night routine.
It's amazing any of us survive to adulthood, isn't it? Courage.
* By "CIO people" I don't mean people who have done CIO. I mean people who tell everyone with a baby to do CIO or they're somehow missing out on the ultimate parenting experience and doing their kids a grave disservice. I'm sure you know them. They're probably waiting for you at the grocery store right now, standing next to the Give that Baby a Pacifier/Get Rid of that Baby's Pacifier people.
** But maybe not always. Remember how my second son was a "cries to release tension" baby, who'd even cry while nursing to sleep? Now that he's a toddler it seems that sometimes he cries to release tension, but sometimes crying gets him more upset. He also won't nap for me willingly. So every day's a crapshoot with him crying and me standing outside the door after 90 seconds trying to figure out if the crying is helping him wind down or just making him more upset. It's charming. I blame my husband, somehow.